More commonly, non-traditional high temperature composite materials, such as ceramic matrix composite (CMC) materials, are being used in applications such as gas turbine engines. Components fabricated from CMC materials have a higher temperature capability compared with typical components, e.g., metal components, which may allow improved component performance and/or increased engine temperatures. Generally, a gas turbine engine includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine generally includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, air is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gases through the turbine section drives the turbine section and is then routed through the exhaust section, e.g., to atmosphere.
More particularly, the gas turbine engine defines a flow path for routing the combustion gases through the engine. Typically, a plurality of nozzle airfoils (or stator vanes) and rotor blade airfoils (or rotor blades) extend within the flow path for extracting kinetic energy from the flow of combustion gases. Commonly, the nozzle airfoils are bonded to or integral with the flow path boundary walls, such that forces or loads on the nozzle airfoils are transferred to the flow path boundary walls at the bonded connection or the transition between the nozzle airfoils and the walls. As such, stress concentrations arise at the bonded connection or transition between the nozzle airfoils and the walls, particularly at the leading and trailing edges of the airfoils. Often, these stresses exceed the material capability of CMC materials, which may discourage the use of CMC materials despite their benefits.
Accordingly, improved flow path assemblies utilizing CMC materials would be desirable. For instance, a flow path assembly including nozzle airfoils that are decoupled from a flow path boundary wall, such that the loads or forces on the nozzle airfoils are transferred through a structure other than the boundary wall, would be beneficial. As another example, a flow path assembly including features for controlling or metering the cooling or purge flow to components of the flow path assembly would be useful.